At the time the typewriter was originally invented, the limiting factor in printing speed was that of the operator. Therefore, the object of design of improvements to early typewriters was means for improving the speed at which the operator could work; that is to say, the speed of operation of such an early typewriter was limited by the rate of data input to it by an operator. Today, the situation is reversed. Digital data processing methods have enabled data to be inputted into a typing or printing machine far faster than the mechanical operations of the machine can be performed. It has therefore been a continuous object of the typewriter and word processor art to improve the speed at which such data can be output onto paper. To this end, the printing industry has made substantial refinements. One refinement which is now well known is to move the impact means with respect to the stationary platen, rather than move the platen with respect to the impact means, since the impact means is generally of lighter weight and therefore possesses less inertia and can consequently be moved faster. A further refinement which has been introduced and which is the subject of co-pending application Ser. No. 833,270 filed Sept. 14, 1977, is to hold the bulk of the printing ribbon and ribbon supply apparatus stationary with respect to the typing machine and only move a small fraction of ribbon exposed in the vicinity of the impact means. In this way, the amount of ribbon weight which must be moved is considerably lowered, thus enabling improvements in the printing speed of the machine. Clearly, flexible leader means must be devised to convey ribbon between a stationary ribbon cartridge and a moving print point. Leaders which have been developed are the subject of co-pending applications Ser. No. 833,257, filed Sept. 14, 1977, Ser. No. 061,880, filed July 30, 1979 and Ser. No. 092,690, filed Nov. 9, 1979.
Parallel to the development of improvements in speed of printing apparatus, specifically including typewriters, have been the improvements made in the convenience of operation of such machines. In particular, it will be appreciated that an inked typewriter ribbon can be a very messy object to handle with one's hands. Hence, it has been an object of the art to develop a type ribbon-containing cartridge which can be snapped in and out of the machine with a minimum of time and effort expended and without coming into contact with the fingers of the operator or other parts of the machine, thus limiting the amount of ink which is rubbed off on various parts of the machine as well as on the print receiving medium or paper. In the context of the stationary cartridge/movable print point application discussed above, it is apparent that there existed a need for a ribbon exposing means which would hold the ribbon in such a way as to make it readily attachable to the machine for printing and which would be readily demountable when a ribbon was exhausted, but which would further not require any threading of the ribbon by the operator; desirably, a snap-in or-out mechanism needed to be provided. Such a ribbon locating means is disclosed in co-pending application Ser. No. 833,352, filed Sept. 14, 1977, now U.S. Pat. No. 4,203,676. The present application involves improvements made thereto, in particular, the present application discloses an improved ribbon locating bridge designed for use with the flexible leader which is the subject of co-pending application Ser. No. 061,880, filed July 30, 1979.